I noticed, while watching The Ten Commandments, that a good number of characters make prophetic predictions about what will happen in the future. And at first, all of them come true. Especially notable is when Bithia makes Mamnet swear not to tell anyone that Moses is Hebrew and warns her that "the day you break that oath will be the last your eyes shall ever see." This prediction comes true, but does so for reasons that Bithia could not have had anything to do with. Even Rameses gets in on the action at one point. But beginning right after Nefertiri kills Mamnet (which is the event that kicks off Moses eventually being kicked out of Egypt), all this breaks down. After that point, only predictions made by Moses come true. Rameses makes some attempts to state what will happen, but even actions over which he has complete control—like whether or not he kills Nefertiri near-ish the end of the movie—do not come out as he predicted. —JurassicMosquito
All bar one: Rameses' promise/prediction to his father on his deathbed that he will make Egypt's greatness feared among the nations. That much is true; Rameses II was known as "the Builder" and basically inducted Egypt into a golden age of prosperity. (Well, aside from the alleged destruction of his entire army by a certain Hebrew God, but that's another story.
You're also forgetting Miriam's warning to store up on water. Moses can be assumed to have told her what was going to happen, but the women say "Miriam is always right!" She did this often and is mentioned in Exodus 15 as a prophet.
The following exchange around the time of the tenth plague:
Nefretiri[[pleading]]: I saved your son. Moses[resigned]]: I... cannot save yours.
Except that.... he totally can. As demonstrated, the plague doesn't care who you are or what your character is - it will kill your first-born if you haven't marked your door with lamb's blood, and will Pass Over you if you do. Joshua does it to Dathan's house to save the woman he loves, which is implied to save Dathan himself as well.note Dathan has a brother, Abhiram, who may be older. Both are seen after the Passover, so whoever was older was saved. Moses himself grants Bithia sanctuary in his own home as well, so he's clearly aware of this. In short, if he had told Nefretiri to grab her son and come to his house he COULD have saved him. This is not Moses being helpless in the face of the will of God, it's him actively choosing to turn his back on the woman he once loved for the sake of his current path. It shows his transformation more than anything else does.
Joshua. How can you find peace or want it, when Rameses builds cities mortared with the blood of our people! You must lead them out of Egypt! Moses. God made a covenant with Abraham that He would deliver the people! Am I the hand of God?
(Um, yeah, you are. Remember Baka? The old guy in the mud pit said "May the hand of God strike him!" for stealing Liliah. A few scenes later you strangled him with his own whip.)
You can see the Stubborn Mule as a bit of foreshadowing for the (eventual) fate of the Israelites—after four hundred years of bondage, he immediately abuses his freedom by refusing to move, even though doing so would prove to be in his best interest.